Filaments and films of acrylonitrile polymers which are free from vacuoles

ABSTRACT

VACUOLE FREE FILAMENTS AND FILMS OF ACRYLONITRILE HOMOPOLYMERS AND COPOLYMERS CONTAINING AT LEAST 80% ACRYLONITRILE, WHICH CONTAIN 0.1 TO 4% OF A COPOLYMER OF ACRYLONITRILE AND DIMETHYLACRYLAMIDE.

United States Patent 3,732,339 FILAMENTS AND FILMS or ACRYLONITRILE POLYMERS WHICH ARE FREE FROM VACUOLES US. Cl. 260-898 13 Claims ABSTRACT OF THE DISCLOSURE Vacuole free filaments and films of acrylonitrile homopolymers and copolymers containing at least 80% acrylonitrile, which contain 0.1 to 4% of a copolymer of acrylonitrile and dimethylacrylamide.

This invention relates to vacuole-free filaments and films of acrylonitrile homopolymers and copolymers.

One of the disadvantages of filaments or film produced from acrylonitrile homopolymers or copolymers, for example with acrylic acid esters or vinyl acetate, is that they contain vacuoles. The effect of the vacuoles is that the filaments and films acquire a more or less matt or dull appearance when treated with water or steam at elevated temperature. Filaments are inevitably exposed during some stage of processing to the action of hot water or of steam; for example, filaments may be so exposed during stretching and crimping, yarns produced from them may, for example, be exposed during dyeing processes, and

made-up fabrics will be exposed during washing and iron- 5 ing. The dulling effect attributable to the vacuoles cannot be prevented and is evidently governed to a large extent by the external conditions, i.e. the intensity and the tempera- .ure of the treatment with water, with the result that the end products obtained from the filaments or films have a far from uniform appearance.

It has now been found that the formation of vacuoles in filaments or films of acrylonitrile homopolymers and copolymers can be significantly reduced, or even avoided altogether, providing copolymers of acrylonitrile with dimethyl acrylamide are added to the spinning solutions of the acrylonitrile homopolymers and copolymers and or ganic solvents, in quantities of from 0.1 to 4%, based on the acrylonitrile polymer.

Therefore, it is an object of this invention to provide filaments and films of acrylonitrile polymers that are free of vacuoles, or the content of vacuoles of which is at least significantly reduced.

This object is accomplished by a filament and a film of acrylontrile polymers, consisting of a mixture of (a) from 99.5 to 96% by weight of an acrylonitrile polymer selected from the group consisting of an acrylonitrile homopolymer and an acrylonitrile copolymer containing at least 80% by weight of copolymerised acrylonitrile, and

(b) from 0.5 to4% by weight of a copolymer of from 80 to 20 mol percent of acrylonitrile and from 20 to 80 mol percent of dimethyl acrylamide.

The filaments and films according to the invention are obtained by a process which comprises mixing in a solvent (a) from 99.5 to 96% by weight of an acrylonitrile polynitrile homopolymer, an acrylonitrile copolymer con- Ice taining at least by weight of copolymerised acrylonitrile, and (b) from 0.5 to 4% by weight of a copolymer of from 80 to 20 mol percent of acrylonitrile and from 20 to 80 mol percent of dimethyl acrylamide and processing the solution thus obtained into filaments and films.

The molecular weight of the copolymer (b) added in accordance with the invention can be varied within wide limits. Broadly speaking, copolymers with K-values [according to H. Fikentscher, Cellulose-chemie 13 (1932), page 58] of from 2 to are effective, copolymers with a K-value of from 25 to 40 being particularly favourable. The percentage composition of the copolymers of acrylonitrile and dimethyl acrylamide added in accordance with the invention can also be varied within wide limits. Thus, vary boardly, copolymers of dimethyl acrylamide and acrylonitrile containing from 20 to 80 mol percent of dimethyl acrylamide, show the require effect. Optimum activity is governed to a lesser extent by the composition of the basic mat-e'rial used for the fibres or the film [component (a) It is surprising that, even when added in such small quantities, the copolymer of dimethyl acrylamide and acrylonitrile should provide such a favourable effect, because a similarly prepared copolymer, comprising, for example, monomethyl acrylamide and acrylonitrile, is ineffectual. In the case of filaments and films of copolymers of acrylonitrile with up to 20% of a second polymerisable vinyl, vinylidene, acrylic or methacrylic compound, for example, methyl acrylate, methyl methacrylate, vinyl acetate, styrene, vinyl chloride or vinylidene chloride, the effect obtained by the small addition is as intense as that obtained in filaments based on acrylonitrile homopolymers.

. The usual polar solvents for polyacrylonitrile, such as dimethyl formamide, dimethyl acetamide, eth'ylene carbonate, y butyrolactone, dimethyl sulphoxide, or hexamethyl phosphoric acid triamide etc., are suitable organic solvents for use in the preparation of spinning solutions from the mixture according to the invention.

Although it is known from DAS 1,069,614 that the addition of from 30 to 5 parts by weight of a homopoly mer of -an acrylamide derivative corresponding to the general formula -in which R represents hydrogen or methyl, and R and R represent hydrogen or alkyl with 1 to 6 carbon atoms,

or the addition of copolymers comprising at least 50% of these acrylamides' or methacrylamide derivatives to 70 filaments of acrylonitrile homopolymers and copolymers against theformation of vacuoles. The reason for the effect of these polymers on the development of vacuoles is not known, nor is it exhibited by the described polymers obtained from monomers of general Formula I; it is in fact specific to dimethyl acrylamide/acrylonitrile copolymers. Whereas thehydrophilicity and dyeability of acrylonitrile.,,fibres are, improved, for example, by co- Treatment stage:

amide derivatives corresponding to the general formula When addition is effective as a substance which prevents. vacuole formation, significantly clearer films are obtained as early as in stages 1 and 2, but more particularly on completion of stage 4 of the treatment scheme. Flaments CH=C C 5 behave in the same way as. films.

l R I In the following examples, which are to further illusin which R represents hydrogen or methyl, and R repreirate b iilyeiiiion, ail Percentages e y Weight unless sents a lower alkyl radical; these copolymers do not pre- Otherwise lndleaied- T P y Weight relate to Paris vent the development of vacuoles as do the copolymers of y volume as to ilieracrylonitrile and dimethyl acrylamide. added in accord- EXAMPLE 1 ance with the invention. Neither do'the raft l mers and graft copolymers of acrylonitrile rz g of Preparation of the acrylonitrile/dimethyl acrylamide acrylamide or methacrylamide described in US. patent copolymer spevlficatwns, 2,620,324; 549 2,557,191; 330 parts by weight of dimethyl acrylamide and 177 2,775,270 a 2,833,470, corresponding to the general parts by weight of acrylonitrile (molar ratio 1:1) are formula polymerised under nitrogen for 8 hours at 80 C. in 3300 CH:=C-CONR3R| parts by volume of tert-butanol by means of 13.2 parts I t i by weight of azodiisobutyrodinitrile. The first polymer I i flakes appear after 25 minutes. After cooling, the product in which R represents hydrogen or methyl, and R and settles at the bottom of the polymerisation vessel in the R represent hydrogen or alkyl with 1 to 6 carbon atoms; form of a solid, pale yellowish deposit. The supernatant as such or as additives to fibre-forming acrylonitrile polyliquid is run off, the precipitated polymer is washed with mers even in quantities as large as 10%, produce the a mixture of petroleum ether and tert-butanol in a ratio technical effect obtained in accordance with the invention Of 111 d th d i d in v o at 50 C- I s Obtained by adding the copolymers of acrylonitrile a d dimethyl in a yield of 90% and has a K-value of 29.7, as measured acrylammm v in dimethyl formamide at 20 C. Another 5% of polymer The composition of filaments of polymers mixtures used having a K-yaille 0f 20 can be Precipitated from the according to the invention differs fundamentally from that 'buianoi y Petroleum etherd! filaments or polymers according to the aforementioned US. patent specifications in that the filaments according I I EXAMPLE 2 I to the invention consist of polymer mixtures which do not 10% solutions i di h l f id are prepared Contain y graft p y Moreover, the technical effect from a copolymer of acrylonitrile comprising 4.5% of obtainable in accordance With the aforementioned U.S. methyl acrylate and 1% of methacryloyl aminobenzene- Patent Specification is not Obtained y mixing in the benzene disulphonimide having a K-value of 85, alone polymers used in accordance with the invention, either d i h ddi i of 1, 2, 3 d 4% b weight f th as regards the eifeei 011 y y or as r s the copolymer of dimethyl acrylamide and acrylonitrile deprovement in hydrophilicity. Instead, it has surprisingly scribed in Example 1. Films drawn from these solutions been found that, according to the invention, the addition and dried at C. are boiled in water for 1- hour, dried, of less than 4% by weight of copolymers of dimethyl tempered for 20 minutes at 140 C. and then boiled again acrylamide with acrylonitrile is suflicient to prevent the I for 1 hour in water. The dulling of the films is assessed development of vacuoles in filaments and films. as follows:

Films boiled for 1 hour Boiled I Moist Dried Tempered at 140? C. ii u r No additive Distinctly hazy, White specs. Distinctly hazy, white specs. Clear, isolated white specs. Hazy. t$itflatiaa::"":Xi1li tfi. 3ffi"* "3 i ffifit cl b i hazymngmedgt" it; 1 With 3% of additive. 'Minimal,hazin Very little hazing d Do. With 4% of additive Clear do Do.

' The dyeability of the fibres and films can be'irnproved,

in known manner, if component (a) of the starting material, which is employed in a quantity of at least 96% by weight, comprises a small quantity, usually about 1% by 1 Films of the acrylonitrile polymer or of the mixture of acrylonitrile polymer (a) with copolymer (b) are treated in accordance with the following scheme:

(1) Boiling for 1 hour in water at 100 C.,

(2) Drying for 1 hour at 50 C.,

(3 Tempering for 20 minutes at 140 C., and

(4) Boiling for 1 hour in water at 100 C. I

The following results are obtained from tests conducted I on a film of a copolymer (a) without the addition of (b):

Appearance of the film 1 Hazy 2 a Hazy 3 Clear Dulling under the influence of boiling water is significant reduced by the addition of only 1% by weight of the copolymer indicated, and is eliminated altogether by additions in excess of 2% by weight.

COMPARISON EXAMPLE 1 3 Preparation of an acrylonitrile/monomethyl acrylamide copolymer at 50 C. The mother liquor does not contain any polymeric material that can be precipitated with petroleum ether. A yieldof 83% is obtained; the K-value, measured in dimethyl formamide at 25 C., being 71.

COMPARISON EXAMPLE 2 (a) 99.5 to 96% by weight of an acrylonitrile homopolymer or copolymer with methyl acrylate, methyl SOIutlons 111 yl formffilmlde are P p methacrylate, vinyl acetate or styrene containing 80 from a copolymer of acfylonltnle W1t h 43% of y to 100% by weight of polymerized acrylonitrile; and acrylate and 1% of methacryloylaminobenzene-benzene 5 (b) 05 t 4% b i h f a copolymer of 30 to disulphonirnide, alone and with the addition of l, 2, 3 and l percent l i il d 20 to 80 l percent 4% by weight of the copolymer of monomethyl acryldimethyl acrylamide, amide an acryloni ril described in mp ri n EXamand processing the solution thus obtained into filaments pie 1. Films drawn from these solutions and dried at or films. 50 C. are boiled in water for 1 hour, dried, heated for 10 8. The process of claim 7 wherein said component (a) 20 minutes at 140 C., and then boiled in water again for is a copolymer of acrylonitrile and methyl acrylate or 1 hour. The dulling of the films is assessed as follows: methyl methacrylate.

Film boiled for 1 hour I Boiled for 1 M i t Dried Tempered at 140 0. hour 3$lil$iii3l3f::: assesses; 333. 33.3333entrees; 333.3as%s23;:fi- 3333 With 2% of additiv do dn Do With 3% of additiv fin Do. With 4% of additiv do Do,

The copolymer of monomethyl acrylamide and acrylo- 9. The process of claim 7, wherein said mixing is carnitrile does not prevent the films from dulling in boiling ried out in a solvent selected from the group consisting water, but instead makes them even more hazy in apof dimethyl formamide, dimethyl acetamide, ethylene carpearance than they are without the addition after tem- 25 bonate, 'y-butyrolactone, dimethyl sulphoxide and hexa- Psring t 140 C, methyl phosphoric acid triamide.

w we l i i 10. The process of claim 7, wherein said copolymer 1. A vacuole-free filament or film of polymerized acry- (b) has a K-value of from 10 to 100. lonitrile consisting essentially of amixture of The process of claim 7, wherein said copolymer (a) 99.5 to 96% by weight of an acrylonitrile homo- 0 (b) has a K-value of from 25 to 40.

polymer or copolymer with inethyl acrylate, methyl 3 12. The process of claim 7, wherein said component methacrylate, vinyl acetate, or styrene containing 80 (21) comprises a comonomer with acidic or basic groups. to 100% by weight of polymerized acrylonitrile; and 13. The process of claim 12, wherein said comonomer (b) 0.5 to 4% by weight of a copolymer of 80 to 20 wi h acidic or basic groups is selected from the group conmol percent acrylonitrile and 20 to 80 mol percent sistmg of styrene sulphonic acid, a disulphonimide, vinyl dimethyl acrylamide. v pyridine, dimethylaminoethyl methacrylate and a snlpho- 2. The filament or film of claim 1 wherein said combetalne. ponent (a) is a copolymer of acrylonitrile and methyl References Cited acrylate or methyl methacrylate. UNITED STATES PATENTS 3. The filament and film of claim 1, wherein said 00- 40 01 mer b has a P-value of from 10 to 100. 2331326 4/1958 Cool/e1 6t 26032.8 p 4 Thai fil ament and film of claim 11, wherein said co- 3039524 6/1962 Belck 28-82 polymer (b) has a K-value of from 25 to 40. 3,139,621 6/1964 Stewart 260---41 5. The filament and film of claim 1, wherein said com- OTHER REFERENCES ponent (a) comprises a comonomer with acidic or basic 45 Schildknecht: Vinyl and Related Polymers p 2 gmups' pp. 282-286.

6. The filament and film of claim 5, wherein said comonomer with acidic or basic groups is selected from the SAMUEL BLECH Primary Examiner group consisting of styrene sulphonic acid, a disulphonimide, vinyl pyridine, dimethylaminoethyl methacry- SECCURO, Assistant EXamlIleI' late and a sulphobetaine.

7. A process for the production of vacuole-free filaments or films which comprises mixing in a solvent 2642l1; 260-30.4 N, 30.6 R, 30.8 DS, 32.6 N, 895

r UNlTED STATES PA ENT OFFICE I CERTIFKCATE UF CORRECTION Patent NO. 3,732,339 Date May 8, 1973 lnventofls) Carlha'ns Suling et al Ir-is certifiedthat error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

' 1 Column 1; lihe 22, "film "should read "films- Column 2,- line l 9 "require" shofild' read --requi red*-. Column line 4; ,"Flaments" should read -filaments-.

Column] 5, line 41 C1a'im '3' "Pva .lue should read --K-value.

Signed and sealed this 19th day, of November 1974.

(SEAL) Attest:

McCOY M-. GIBSON JR. 1 c. MARSHALL- DANN Attesting Officer Commissioner 'of Patents USCOMM-DC 60376-P69 w u.s. GOVERNMENT PRINTING OFFICE: I969 o-ass-Jal FORM PC4050 (10-69) r I, I r v I 

